PcF is a 52 residue protein factor of two alpha helices, containing a 4-hydroxyproline and three cysteine bridges. The presence of the hydroxyproline is unique in relation to other fungal phytotoxic proteins. The protein has a high content of acidic side-chains implying a lack of binding with lipid-rich components of membranes and appears to be an extracellular phytotoxin that causes leaf necrosis in strawberries.

1: Phytotoxic protein PcF, purification, characterization, and cDNA sequencing of a novel hydroxyproline-containing factor secreted by the strawberry pathogen Phytophthora cactorum. Orsomando G, Lorenzi M, Raffaelli N, Dalla Rizza M, Mezzetti B, Ruggieri S; J Biol Chem. 2001;276:21578-21584. PMID:11262411